Bon Bon appetit

If you only do one thing, you'd better do it well. Tim and Jenny Holloway's one thing is banh mi, and at their new Wicker Park sandwich shop, they're doing the classic Vietnamese sandwiches very well.

Bon Bon Vietnamese Sandwiches started life in February as a tiny carryout-only sandwich counter at the front of meal-prep service My Gourmet Kitchen, but there were always plans for something bigger. My Gourmet Kitchen was about to close, and the Holloways had designs on expansion. About three weeks ago, after a three-week closure to reconfigure the space, Bon Bon launched in earnest. The shop's still a counter-service operation, but the orange- and green-walled room is now filled with a garage sale's worth of mismatched tables and retro chairs.

The secret to great banh mi is great bread, and Bon Bon gets theirs from one of the best sources in town, Lincoln Square's Nhu Lan Bakery. Squishy soft with an exterior that flakes away when you bite into it, it's the perfect base for all five varieties of banh mi the shop turns out: classic, minced pork (seasoned with onions and fish sauce), char siu pork, gingered chicken and portobella ($3.95 each). Each sandwich gets a generous smear of mayo and a salad of julienned carrots, cucumber and daikon radish, plus some fresh cilantro. The crowning touch, a hit of fiery burnt red sriracha, is left to you -- bottles are at the counter.

Back when Bon Bon was just a little counter in the corner of My Gourmet Kitchen, we fell hard for the char siu pork banh mi, filled with sweet barbecued pork. We've since discovered the classic version, spread with a salty pate and layered with slices of head cheese and Vietnamese ham (also courtesy of Nhu Lan), and it's just as addictive.

Confession: When we said that Bon Bon only does one thing, we fibbed a little. They do make only one kind of food. But there's also Vietnamese coffee and bubble tea. The coffee, icy and thick with sweetened condensed milk, is a good option as part of the $6.50 sandwich-and-coffee combo meal, but if you've got a few quarters to blow (have we mentioned the meter-free street parking?), you'll want to have fun with the bubble teas ($2.95). Flavor choices are predictably brief (lychee, coconut, honeydew, mango, taro, milk tea, matcha green tea) but you can combine any two flavors for the same price. Tim Holloway's favorite? Taro-matcha -- and he may be on to something.

Sometime soon, Bon Bon may ditch the single-item focus to add soups, salads and sides to the menu. But as long as they don't lose focus, we can't complain.